import java.util.Scanner;

class Animal{
    public void move(){
        System.out.println("动物可以移动");
    }
}
class Dog extends Animal{
    public void call(){
        System.out.println("狗可以叫");
    }
}
public class Work {
    public static void main5(String[] args) {
        Animal dog=new Dog();
        String frist="abc";
        String two="bc";
        System.out.println(frist.compareTo(two));
    }
    public static void main4(String[] args) {
        Scanner in=new Scanner(System.in);
        while (in.hasNext()) {
            String a = in.next();
            String b = in.next();
            int x=Integer.parseInt(a,2);
            int y=Integer.parseInt(b,2);
            int sum=x+y;
            System.out.println(Integer.toBinaryString(sum));

        }
    }
    public static String exchange(String a,String b) {

        StringBuilder sum=new StringBuilder();
        for (int i = 0; i < a.length(); i++) {
            char temp=a.charAt(i);
                if(b.indexOf(temp)>=0){
                    continue;
                }
            else {
                sum.append(temp);
                }
                }
        return sum.toString();
    }
    public static void main(String[] args) {

        Scanner in=new Scanner(System.in);
        while (in.hasNext()){
            String a= in.nextLine();
            String b= in.nextLine();
        String x= exchange(a,b);
            System.out.println(x);

        }
    }

    public  static int sbnq(int n) {
        if (n == 1 || n == 2) {
           return 1;
        }
        else {
            n=(sbnq(n - 1) + sbnq(n - 2));
        }
        return n;
    }
    public static void main2(String[] args) {


        Scanner in=new Scanner(System.in);
        int sum=1;
        while (in.hasNext()){
            int a= in.nextInt();
                System.out.println(sbnq(a));
        }
    }
    public static void main1(String[] args) {
        Scanner in=new Scanner(System.in);
        while (in.hasNext()){
            String a=in.next();
            String b=a.toLowerCase();
            System.out.println(b);
        }
    }
}
